Agricultural/Bioengineering: Dairy Engineering Flashcards
7 cards from real Agricultural/Bioengineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Agricultural/Bioengineering: Dairy Engineering flashcards as text
When sizing a cooling system for a raw milk receiving tank, which parameter is most critical for preventing microbial growth?
Answer: Achieving 4°C within 2 hours of milking to slow mesophilic bacterial growth
Grade A PMO standards require raw milk be cooled to ≤4.4°C (40°F) within 2 hours to inhibit mesophilic pathogens while preventing freezing.
In lactose crystallization for the production of lactose monohydrate powder, what is the primary role of the 'seed' crystals added to the supersaturated lactose solution?
Answer: Seeds provide nucleation sites to initiate controlled crystal growth and prevent amorphous solidification
Seeding with fine lactose crystals provides nucleation sites that direct crystal growth in a controlled manner, producing uniform α-lactose monohydrate crystals rather than a glassy amorphous mass.
A cheesemaker notices that the curd is too soft and not cutting cleanly after rennet addition. Which corrective action is most appropriate?
Answer: Extend the coagulation time or increase the CaCl₂ dose to achieve a firmer gel before cutting
Soft curd indicates incomplete coagulation; extending set time or adding CaCl₂ strengthens the gel network before cutting, preventing curd shattering and fat losses in whey.
What is the purpose of standardizing fat content in milk before processing into a product like 2% reduced-fat milk?
Answer: To comply with legal compositional standards and deliver consistent product to consumers
Standardization blends cream and skim milk streams to achieve the legally defined fat content (2.0% for reduced-fat milk) required by FDA standards of identity.
In an ice cream mix formulation, what is the primary function of an emulsifier such as mono- and diglycerides?
Answer: They promote partial coalescence of fat globules during freezing, improving overrun stability and texture
Mono- and diglycerides displace milk proteins from fat globule surfaces, promoting controlled partial coalescence that creates a fat network supporting air bubbles and giving ice cream its characteristic body.
What does the term 'overrun' mean in the context of ice cream processing?
Answer: The percentage increase in volume due to air incorporation during freezing
Overrun = [(volume of ice cream – volume of mix) / volume of mix] × 100%; typical values are 80–100% for retail ice cream, giving a lighter, airier texture.
In a dairy plant using CIP (Clean-in-Place) systems, what is the correct sequence of cleaning steps?
Answer: Hot water rinse → caustic wash → hot water rinse → acid wash → final rinse → sanitize
Standard dairy CIP sequence: pre-rinse (remove bulk soil) → hot caustic (remove protein/fat) → intermediate rinse → acid wash (remove mineral deposits) → final rinse → sanitizer.